Clamping device



J- W. SHERWOOD CLAMPING DEVICE April 10, 1951 Filed Nov. 12, 1948INVENTOR. 716 All MMQL kuqizwvqlm4/ Patented Apr. 10, 1951 UNITED STATESPATENT OFFICE CLAMPING DEVICE Joseph W. Sherwood, Sapulpa, Okla.

Application November 12, 1948, Serial No. 59,725

The invention pertains to a device for positively gripping structural orwork members such as plates, sheets, beams, channels, etc., andparticularly, to an improved hoisting clamp or grapple for raisingstructural members and placing them at a desired location.

A device such as herein contemplated is needed to hoist structuralmembers to .a suitable level or height of a derrick, building, tank, orother construction, in order that the members may be made available atthe proper position and location needed. Heretofore, it has beencustomary in the present art to employ grapples or hoisting tongs whichare provided with a pair of slips for gripping the member to be hoisted.These devices have a, number of disadvantageous features.

In the first place, slips are customarily mounted in wedge-shaped jawsin such a manner that their gripping action is dependent upon a constantapplication of the weight of the member being lifted. From a safetystandpoint, they are thus very dangerous. That is, back lash may beencountered in the cable line, or the cable or device may run into aprojection in such a manner that the weight of the member being carriedis at least momentarily made ineffective.

Another disadvantageous feature arises from the complexity of theconstruction of these devices. They have heretofore been expensive fromthe standpoint of their initial manufactured cost, as well as from amaintenance standpoint.

One investigator endeavored to avoid a release of the structural membersby providing his device with a pair of dogs to engage the slips, butthis further complicated the device and made it more difficult to insertand remove thestructural members.

The prior methods employed in mounting a device on the hoisting cable orwinch line are also rather complex and present certain disadvantageousfeatures. For example, the general practice has been to secure the lowerend of the cable by a closed loop to a balance frame carrying a pair ofdevices, to a pair of clamping levers which depend upon the tension ofthe cable for the gripping faction exerted on jaws or slips, or to thebody of a device, itself. It is thus apparent that such devices havelittle flexibility in their utilization, and as to a desired locationalong the length of a cable or winch line.

It has thus been an object of my invention to provide a new and improvedform of hoisting clamp or grapple device;

Another object has been to devise a solution to the problems heretoforepresented in the art 3 Claims. (Cl. 294-103) in question, and toincorporate such solution into an improved hoisting clamp;

A further object of my invention has been to provide an inexpensive,practical, simple, and efficient new type of hoisting device which canbe mounted along any portion of the length of a cable or winch line;

A still further object of my invention has been to provide a hoistingdevice that will positively grip a structural member without dependingupon the tension of the hoisting line or the weight of the member tomaintain its gripping action;

These and many other objects of my invention will appear to thoseskilled in the art from the illustrated embodiment of my invention aswell as from appended claims.

In the drawings, Figure l is a top plan view of a device constructed inaccordance with my invention; it also shows the position of the devicewhen it is being verticall suspended from a winch line or cable andwhile carrying a structural member;

Figure 2 is a sectional view of the device taken along the line IIII ofFigure 1 and also illustrates its position when it is verticallysuspended from a cable;

Figure 3 is an enlarged view in elevation of a tooth insert or grippingelement of the device shown in Figures 1 and 2.

As illustrated particularly in Figures 1 and 2, my device is providedwith a yolk or main body In which may be a casting of a suitable metal,such as high tensile steel. As shown particularly in Figure 2, the body[I] has a, substantially heavier construction of rectangularcross-section towards its outer, member-gripping, or bottom end (whensuspended). It also has an inclined, tapered, or upwardly-convergingportion (when suspended) that is provided with a line or cablereceivinghole or opening i l therethrough.

In Figures 1 and 2, for the purpose of more clearly illustrating autilization of my device, I have shown a structural or work member 30, acable or winch line 3|, and an adjustable cable clamp or look 32. Asshown in Figure 2, the cable 3| is loosely threaded through the hole orbore I l and the device is held in a, desired position on the cable bythe clamp 32 which may be of any suitable construction. To distinguishfrom the device, the member 3| the cable 3!, and the clamp 32 are shownby dot and dash lines.

Referring particularly to Figure 1, the body It is bifurcated or forkedat its outer or lower end to provide a slotted opening to receive thework 3 member 30 which is to be raised. Such slot or opening is definedby opposite mouth or fork walls l2 and [3. The fork wall 13 is, as shownparticularly in Figure 1, provided with a counterbore l4 and a tappedbore l5 to threadably receive a capstan-headed, adjustable clampingscrew I6 transversely or endwise therethrough.

The capstan screw I6 is provided with male threads ll and a taperedclamping or membergripping end portion is which, as shown by the dottedlines of Figure 1, has a concave, conelike depression therein to providea circular or annular peripheral grip edge thereabout. The outer end ofthe capstan screw [6 is provided with a head [9 through which atransverse hole 20 extends to receive a turn bar or rod, so that it maybe tightened down and loosened with respect to a structural or workmember, such as 36.

The other fork wall I2 of the body I0 is provided with a removable,serrated or grip element 2! which is inset within a depressed portionthereof. A tapped bore 27 extends transversely through the fork wall [2and in substantial axial alignment with the bore 55 of the opposite forkwall it. The bore 21' is adapted to receive a threaded stem 29 of asetscrew. The setscrew is also provided with a slotted head portion 28adapted to fit within a counterbore 25 of the element 2!, see Figures 2and 3. The stem 29 extends through bore 26 of the element 2], and withthe depressed or inset wall portion of the fork wall I 2, securely andpositively mounts or holds the jaw or grip element 2| in position withinthe fork wall [2.

Referring particularly to Figure 3, I have shown details of theconstruction of the jaw or grip element 2|. It will be noted that it isprovided with a plurality of outwardly-extending teeth and that eachtooth has an inclined back face 23 of relatively steep pitch and aninclined front face 24 of lesser pitch.

Referring to Figure l, the faces 23 and 24 of each tooth meet in awork-holding wedge edge that has a backward pitch with respect to thework member 30 that is to be carried. It will also be noted that thefirst or lower tooth has a root 22 that is of substantially square orrectangular outline and is deeper than the pointed, or angleshaped rootedges of the following teeth.

I have determined that an improved .gripping action is obtained byemploying the root 22. In the first place, it provides a greater spacingbetween the first and second teeth; this gives an improved holdingaction adjacent the outer or lower end of the grip element 21, andpermits a slight pivot action of the work member 33 about the grippingend portion is of the capstan screw it without permitting the workmember 3D to slip. It will also be noted that the tapered grip endportion 18 is in substantial alignment with the counterbore 25 of theelement 2!, and tends to flex the member 36 about the counterbore and towedge it tightly against the teeth of the element 21.

I have shown, see particularly Figure 2, that the body N3 of my deviceswings into a substantially vertical plane when the winch line 31 isbeing raised due toits shape and manner of suspension. The slope orconverging upper portion of the body H! has an inclined engagement withthe clamp 32, see Figure 2, to provide the winch or cable 3! with apronounced radius engagement with the wall of the hole II. This alsoprovides a simple way of mounting my device on a winch or cable linewithout a balancing cradle or frame and without requiring the use of aclosed cable loop. The clamp 32 may be moved to any position along thecable 3|, in order that other portions of the cable may be employed forother purposes, such as to carry additional devices in a spacedrelationship along its length.

My device positively grips the work member 30 which is being carried andcannot release such member until a turn bar or rod has been insertedthrough the hole 20 and the screw 16 loosened. It is apparent that ahigh degree of safety is attained. In addition, after the structural orWork member 30 has been raised to a proper height, a worker can moveit'horizontally to a suitable position without any danger of it fallingout of the device. I have thus been able to eliminate the variousdisadvantageous features of the prior art devices and to provide ahighly improved, simplified, and less expensive and complicated clamp orgrapple device.

What I claim is:

1. A grip hoisting clamp adapted to be mounted on a hoist line forpositively suspending a heavy structural member regardless of whether ornot its weight is effective under such suspension which comprises, arelatively heavy integral body having a pair of front and back facesrepresenting major dimensions of said body and circumscribed by an edgewall representing the thickness of said body, said body being of heavysubstantially rectangular thickness-cross-section upwardly from itslower end portion and of a converging taper-cross-section upwardly fromsaid rectangular section to its upper end portion, a hoist line mountextending through said tapered section between the front and back facesand adjacent the upper end portion of said body to suspend said bodyvertically from the hoist line, a pair of jaws in said rectangularsection and open upwardly from the lower end portion thereof, said jawshaving a pair of opposed substantially planar clamp faces defining anopen vertical slot in said body, a threaded bore extending transverselyfrom the edge wall through one of said jaws substantially parallel tothe front and "back faces of said body into one of said clamp faces, arelatively heavy capstan-headed adjusting screw having a threaded stemadjustably mounted in said threaded bore to extend therealong from theedge wall, said stem terminating in a tapered clamping end portionadapted to extend inwardly from said one clamp face to abut a structuralmember to be gripped, a grip element, said other clamping face having adepressed portion therein in a substantially aligned relationship withrespect to said threaded bore, said grip element being inset within saiddepressed portion and having .a series of teeth in its outer faceprovided with a backward pitch and projecting outwardly into the openvertical slot from said other clamp face to abut against an oppositeside of the structural member to be gripped, a headed set screw insetwithin said grip element and extending along said other jaw between thefront and :back faces of said body .to secure said grip element inposition on said other jaw, said grip element having a lower toothpositioned in a downwardly olfset relationship with respect to thetapered end portion of the stem of said capstan-headed screw, said lowertooth having an enlarged root spacing with respect to the next tooth ofsaid grip element, said capstan-headed screw being adapted to securelyclamp a structural member against said grip element while the memberextends 5 downwardly from the slot defined by the clamp faces of saidpair of jaws.

2. A grip hoisting clamp as defined in claim 1 wherein, the tapered endportion of the stem of said capstan-headed screw has a cone-likedepression therein defining an annular peripheral grip edge thereabout,and said enlarged root spacing is substantially rectangular and deeperthan the root spacing between the other teeth of said grip element.

3. A grip hoisting clamp as defined in claim 1 wherein, the hoist lineis a cable adapted to extend through said hoist line mount to suspendsaid body as a pendulum downwardly therefrom, and a clamp is adapted tobe mounted on the line in abutment with one of the faces of said body toposition said body on the line.

JOSEPH W. SHERWOOD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

